This invention relates crystalline 9-E-(O-methyl)oxime of 11,12-dideoxy-3-de(2,6-dideoxy-3-C-methyl-3-O-methyl-.alpha.-L-ribohexopyr anosyloxy)6-O-methyl-12,11 -(iminocarbonyl-(2-(3-(4-(3-pyridinyl)-1H-imidazol-1-yl)propyl)hydrazono)) -3-oxoerythromycin wherein said crystalline compound is the free base of said compound (including the hemihydrate of said free base) or the mesylate (methanesulfonic acid) salt of said compound. The crystalline compound of this invention is useful as an antibiotic agent in mammals, including man, as well as in fish and birds. The compound of the present invention is a broad-spectrum macrolide antibiotic that is effective against infections caused by certain gram-positive and gram-negative bacteria as well as protozoa.
A non-crystalline, amorphous form of 9-E-(O-methyl)oxime of 11,12-dideoxy-3-de(2,6-dideoxy-3-C-methyl-3-O-methyl-.alpha.-L-ribohexopyr anosyloxy)-6-O-methyl-12,11 -(iminocarbonyl-(2-(3-(4-(3-pyridinyl)-1H-imidazol-1-yl)propyl)hydrazono)) -3-oxoerythromycin is referred to in PCT international patent application number PCT/IB98/00741, filed May 15, 1998, which is incorporated herein by reference in its entirety. The crystalline compound of the present invention is believed to be more stable than the amorphous compound referred to in the foregoing PCT application, which facilitates the manufacture of precise dosage forms of the compound for pharmaceutical use and improves the shelf-life of the compound. The crystallization of the amorphous compound significantly improves the purity of the compound which further facilitates the preparation of precise and safe dosage forms of the compound for pharmaceutical use. Further, the crystalline hemihydrate form of the free base is non-hygroscopic which is advantageous in the manufacture of accurate dosages.